Intake manifolds including short runner valves and manifold tuning valves are known for use in modern fuel injected engines. These systems have provided improvements in performance for today's engines. Present designs, while generally suitable, still have many areas where improvements in both manufacturing and operation are desirable. Some of the current problems in need of solutions are set forth below.
Because the performance of the engine is directly related to the quickness and efficiency of opening and closing short runner and manifold tuning valves, it is desirable to have the valves operate as friction free as possible. One of the greatest friction areas is along the actuating shafts of the short runner valves. Certainly, using relatively ample clearance in the fittings for these shafts allows low friction operation. However, these clearances also may produce chatter if left unchecked. U.S. Pat. No. 5,992,370 teaches biasing of the shafts for reducing shaft “chatter”. Such biasing assemblies are very effective in reducing noise. However, shaft biasing does increase friction, somewhat reducing response time. Therefore, it is desirable to provide a lower friction anti-chatter device.
A second area needing to be addressed is the problem of sticking or binding valve plates. Of course, it is desirable to have valve plates which completely seal off the short runner passages. However, if the plates are not set up properly, they may bind. This is typically due to the thermal expansion of the various parts during warm-up of the engine. There is a need to provide valve plates which prevent binding during thermal expansion of the manifold. Additionally, proper synchronized closure of groups of valves connected on separate shafts is problematic. If for some reason, the plates are not mounted properly, full closure is not realized.
Additionally, there remains a need in the art for providing an improved method for creating an effective sealing arrangement for a manifold tuning valve.